Location-based services (LBSs) generally refer to information services accessible with mobile devices through a mobile network, such as those defined by the Worldwide Interoperability for Microwave Access (WiMAX) standard (IEEE 802.16). An LBS utilizes the ability to make use of the geographical position of the mobile devices. LBS services include services to identify a location of a person or object, such as discovering the nearest banking cash machine or the whereabouts of a friend or employee. LBS services can also include parcel tracking and vehicle tracking services. Furthermore, LBS can also include personalized weather services and even location-based games.
Due to the popularity and potential of LBSs, demand and usage of location information of a mobile device have been increasing sharply.